src/bin/pg_upgrade/TESTING

THE SHORT VERSION
-----------------

On non-Windows machines, you can execute the testing process
described below by running
	make check
in this directory.  This will run the shell script test.sh, performing
an upgrade from the version in this source tree to a new instance of
the same version.

To test an upgrade from a different version, you must have a built
source tree for the old version as well as this version, and you
must have done "make install" for both versions.  Then do:

export oldsrc=...somewhere/postgresql	(old version's source tree)
export oldbindir=...otherversion/bin	(old version's installed bin dir)
export bindir=...thisversion/bin	(this version's installed bin dir)
export libdir=...thisversion/lib	(this version's installed lib dir)
sh test.sh

In this case, you will have to manually eyeball the resulting dump
diff for version-specific differences, as explained below.


DETAILS
-------

The most effective way to test pg_upgrade, aside from testing on user
data, is by upgrading the PostgreSQL regression database.

This testing process first requires the creation of a valid regression
database dump.  Such files contain most database features and are
specific to each major version of Postgres.

Here are the steps needed to create a regression database dump file:

1)  Create and populate the regression database in the old cluster.
    This database can be created by running 'make installcheck' from
    src/test/regress.

2)  Use pg_dump to dump out the regression database.  Use the new
    cluster's pg_dump on the old database to minimize whitespace
    differences in the diff.

3)  Adjust the regression database dump file

    a)  Perform the load/dump twice
        This fixes problems with the ordering of COPY columns for
        inherited tables.

    b)  Change CREATE FUNCTION shared object paths to use '$libdir'
        The old and new cluster will have different shared object paths.

    c)  Fix any wrapping format differences
        Commands like CREATE TRIGGER and ALTER TABLE sometimes have
        differences.

    d)  For pre-9.0, change CREATE OR REPLACE LANGUAGE to CREATE LANGUAGE

    e)  For pre-9.0, remove 'regex_flavor'

    f)  For pre-9.0, adjust extra_float_digits
        Postgres 9.0 pg_dump uses extra_float_digits=-2 for pre-9.0
        databases, and extra_float_digits=-3 for >= 9.0 databases.
        It is necessary to modify 9.0 pg_dump to always use -3, and
        modify the pre-9.0 old server to accept extra_float_digits=-3.

Once the dump is created, it can be repeatedly loaded into the old
database, upgraded, and dumped out of the new database, and then
compared to the original version. To test the dump file, perform these
steps:

1)  Create the old and new clusters in different directories.

2)  Copy the regression shared object files into the appropriate /lib
    directory for old and new clusters.

3)  Create the regression database in the old server.

4)  Load the dump file created above into the regression database;
    check for errors while loading.

5)  Upgrade the old database to the new major version, as outlined in
    the pg_upgrade manual section.

6)  Use pg_dump to dump out the regression database in the new cluster.

7)  Diff the regression database dump file with the regression dump
    file loaded into the old server.